DC5: Stimulating biodegradation of organic pollutants towards VFA via stress-induced fermentation

Project title: Stimulating biodegradation of organic pollutants towards VFA via stress-induced fermentation (WP2)

Host Institution: KU Leuven

Country: Belgium

Supervisor: Lise Appels (PhD promoter); Co-supervisors: Maria Westerholm (SLU)

Objectives: to steer mixed-culture anaerobic fermentation processes towards a higher degradation efficiency of pollutants while simultaneously increasing the VFA-yield.

DC5 will investigate the impact of 3 different stressors (low & high pH, pollutant presence & concentration, temperature – 30-55°C) on the adaptive response of the microbial community during anaerobic sludge fermentation. The response will be monitored on 5 levels: (i) gene expression levels, (ii) mixed-culture community activity and dynamics, (iii) VFA concentration and composition, (iv) ammonia yield and (v) pollutant degradation/removal efficiency. DC5 will employ lab-scale bioreactors (Type Eppendorf BioFlo® 320) for the conversion of sludge containing different levels of pesticides (desphenyl-chloridazon, Fluroxypyr), PFAS (PFNA, PFOA) and heavy metals. Long-term tests in continuous operation will be foreseen to allow community adaptation to the external stressors and to generate insights in long-term stability of these processes for future industrial application. The effects of the addition of the hydrochar (DC2) and engineered biochar (DC7) on increasing pollutant degradation during bioconversion through improving the DIET and microbial colonisation rate will be studied. In addition, pre-treated sludges from DCs 3&4 will be investigated for their fermentation potential via lab-scale batch assays. DC5 will carry out pot trials simulating soil application of the obtained digestate. DC5 will use the results to build a predictive model (based on e.g., ADM1), extendable to other types of sludge and other pollutants from the same classes.

Expected Results: Proof-of-Principle of enhanced pollutant degradation via anaerobic fermentation towards high ammonia- & VFA-yields.

Enrolment in Doctoral degree(s):KU LEUVEN Arenberg Doctoral School of Science, Engineering and Technology (BE)

Planned secondments:

• European Biogas Association (Sup.: Marina Pasteris): M13-15 (3 months): Training on interactions of industry, governmental and research organizations, and influence of European associations on the EU biogas market and related sectors. Inventory analysis on biogas potential from industrial wastewater throughout EU.
• Raiz (Sup.: Luis Machado): M35-38 (4 months): Training on the forestry biomass-based value chain, competitiveness and sustainability aspects of the pulp and paper sector, and existing and innovative waste management applications.